FIG. 1 illustrates a conventional current circuit 100 having a diode coupled n-channel transistor 120 coupled to a capacitor 150 to provide a bias voltage BIAS. A current source 110 is coupled to provide a reference current IREF to the current circuit 100. In operation, the current circuit 100 provides the IOUT current to maintain a stable BIAS voltage on the capacitor 150. For example, where the BIAS voltage is balanced, that is, the BIAS voltage is neither increasing or decreasing due to the IOUT current, the transistor 120 is biased to conduct a current IO1 that is equal to the IREF current. The IOUT current is 0 for this condition. In the case where BIAS voltage on the capacitor 150 is less than the balanced BIAS voltage, the transistor 120 is made less conductive, and as a result, the IO1 current decreases. The decrease in the IO1 current causes the IOUT current to increase and charge the capacitor 150 to increase the BIAS voltage. As the increasing BIAS voltage returns to the balanced BIAS voltage, the IO1 current increases to be equal to the IREF current, thus the IOUT current no longer charges the capacitor 150. In the case where the BIAS voltage is greater than the balanced BIAS voltage, the transistor 120 is made more conductive and the IO1 current increases. The increase in the IO1 current causes the IOUT current to be drawn from the capacitor thereby discharging it to reduce the BIAS voltage. As the decreasing BIAS voltage returns to the balanced BIAS voltage, the IO1 current decreases to be equal to the IREF current, thus the IOUT current no longer discharges the capacitor 150.
As illustrated in the previous discussion, the current circuit 100 adjusts to provide a stable BIAS voltage. It may be desirable, however, to have alternative current circuits. For example, where reducing power consumption is desirable, providing a current circuit that can be used to provide a BIAS voltage using less current than the conventional current circuit, such as current circuit 100, may be desirable. Another example is where a faster response, that is, the ability for a current circuit 100 to stabilize a BIAS voltage, is desirable, a current circuit providing increased response may be desirable.